With respect to demands for increasing speed, decreasing size, saving energy, and the like in printers in recent years, a decrease in temperature of a fixing unit of a heat roller type has been advanced. For this reason, low-temperature fixability is required in toners. Further, in order to improve fixing failure according to an increase in temperature of the fixing unit during continuous printing, a demand for hot offset resistance and a balance between material dispersibility (particularly, dispersibility of a release agent) with respect to oil-less fixing and hot offset resistance are also required in toners as well as low-temperature fixability.
Binder resins for toners have a large influence to toner performances as described above. As the binder resins for toners, for example, polystyrene resins, polyester resins, epoxy resins, polyamide resins, and the like are known.
The low-temperature fixability of the toner is improved, for example, by blending a release agent such as a wax with the toner.
The hot offset resistance is improved, for example, by increasing high-temperature elasticity of the toner.
For example, Patent Literature 1 discloses a toner that is obtained by dissolving or dispersing, in an organic solvent, a master batch in which a colorant is dispersed in a binder resin for toners such as a polyester resin, a resin identical to or different from the binder resin for toners, and a release agent such as a wax, subjecting the resultant product to emulsification dispersion in an aqueous medium, and then coagulating the emulsion.